There is an ongoing concern in the tobacco industry to produce cigarettes having wrappers which reduce the ignition proclivity of the smoking article, or the tendency of the smoking article to ignite surfaces which come into contact with the lit smoking article. Reports have been made of fires attributed to burning cigarettes coming into contact with combustible materials. A justifiable interest exists in the industry to reduce the tendency of cigarettes, or other smoking articles to ignite surfaces and materials used in furniture, bedding, and the like upon contact.
Thus, a desirable feature of smoking articles, particularly cigarettes, is that they tend to self-extinguish upon being dropped or left in a free burning state on combustible materials.
It has long been recognized in the tobacco industry that the cigarette wrapper can have a significant influence on the smolder characteristics of the cigarette. In this regard, various attempts have been made in the art to alter or modify the cigarette wrappers in order to achieve the desired tendency of the cigarette to self-extinguish, or in other words to reduce the ignition proclivity characteristics of cigarettes.
The prior art describes the application of film-forming solutions to cigarette paper to reduce the paper permeability and control the burn rate. It has been shown that when these materials have been applied in discrete areas along the length of the cigarette, the cigarette shows a reduced propensity to ignite a substrate and tends to self-extinguish.
U.S. Pat. No. 5,878,753 to Peterson, U.S. Pat. No. 5,820,998 to Hotaling, et al., U.S. Pat. No. 6,779,530 to Kraker, and U.S. Pat. No. 6,725,867 to Peterson, which are incorporated herein by reference, for example, describe a smoking article wrapper being treated with a film-forming solution to reduce ignition proclivity. U.S. Pat. No. 5,878,754 to Peterson which is also incorporated herein by reference describes a smoking article wrapper being treated with a non-aqueous solution of a solvent soluble polymer dissolved in a non-aqueous solution to reduce ignition proclivity.
Although many improvements have been made in the art, there is still a need for an improved method for producing a smoking article with reduced ignition proclivity properties. For example, one challenge that has been facing manufacturers has been the ability to create the discrete areas with uniform properties. In this regard, a need currently exists for a process for forming treated areas on a paper wrapper in which the treated areas on each wrapper and the treated areas from wrapper to wrapper do not vary substantially in their properties and characteristics. A process capable of controlling the properties of the treated areas will lead to the formation of smoking articles having more predictable burning characteristics.